Pipe wiper system

ABSTRACT

A pipe wiper assembly for stripping fluid from well strings has a container, with side walls, for use above the well head. Inside the container a frame is situated for some limited horizontal movement and the frame contains a pair of wiper blades in a horizontal guideway. The wiper blades move in opposite directions in the guideway between open and closed positions by way of forces provided by fluid power cylinders mounted on the frame and attached to the wiper blades. In the open position, the wiper blades are clear of the well string and in the closed position they are pressed against the well string. The wiper blades are vertically stacked in the closed position and overlap to assure full circumferential wiping of the well string. The frame is tethered to the container to prevent rotation due to well string friction. The cylinders are provided with fluid power by way of flexible hoses.

This invention pertains to a pipe wiper device to be used at well headsto strip fluids from the outer surface of tubular articles being pulledfrom a well.

BACKGROUND OF THE INVENTION

When a tubular string is pulled from a fluid filled well some fluidclings to the outer surface of the string, or pipe. The pipe isseparated into selected lengths for handling and usually standsvertically on the rig floor, extending up into the derrick, untilreassembled and put back into the well. The fluid drips down on the rigfloor to create waste, hazard and pollution. It has, for years, been apractice to use some means to strip the fluid from the pipe surface asthe string moves upward through the drilling floor and to direct therecovered fluid back to the fluid handling system.

The pipe wiper system is commonly placed below the drilling floor, andabove the well head. The well head is usually fitted with a funnelopening upwardly near the wipers to gather the stripped fluid. Some pipewipers are simple bushings of resilient material that snugly fit thepipe but are sufficiently resilient to stretch over tool joints movingupward while the bushing is tethered to the structure. Such bushingshave to be removed for the passage of stabilizers and other largecomponents of the string. Other pipe wipers have laterally movablearcuate wiper blades that can be forced against the pipe for wipingaction or moved away to clear the string. Such wiper blades areresilient and shaped to overlap when against the pipe. To permitoverlap, the blades are usually spaced apart vertically. Such wipersystems are usually fluid powered for opening and closing on the pipe,with the fluid power controlled by valves accessible to personnel on therig floor.

The drill string, when suspended from the hook, usually moves laterallyaround the interior of the larger well head. The pipe wiper must acceptthis lateral movement and still perform as intended.

There is a need for a wiper system that can be opened and closed on thepipe by action of fluid power controlled by the driller, yet of suchcompactness that it can be installed and removed through the opening inthe rig floor.

It is therfore an object of this invention to provide a pipe wiperassembly in a containing funnel, attachable to the well head, withinwhich a wiper blade assembly can move laterally in sympathy withmovement of the pipe string.

It is another object of this invention to provide a pipe wiper assemblysufficiently compact to be lowered into position, and removed, throughthe rotary table opening in tbe rig floor.

It is a further object of this invention to provide a pipe wiperassembly that is compact and responsive to fluid power controlmanipulations to open the wiper to clear the pipe string and to closethe wiper to strip fluid from the pipe.

These and other objects, advantages, and features of this invention willbe apparent to those skilled in the art from a consideration of thisspecification, including the attached claims and appended drawings.

SUMMARY OF THE INVENTION

An upwardly opening funnel shaped container is arranged for attachmentto the well head. A pipe wiper blade assembly with two opposed wiperblades fits into the container with some lateral clearance to admit somelateral movement therein. The wiper blades are situated within a framecomprising a generally central opening to accept pipe therethrough,lateral tracks to confine and direct laterally movable wiper blades, aplurality of fluid power cylinders attached to the frame and arranged tomove the wiper blades between an open position, clearing the pipe, and aclosed position, against the pipe, and a plurality of tethers to attachthe frame to the container to prevent the frame from rotating when piperotates. The blades are arcuate shaped, at least part elastomer, andarranged to somewhat overlap where the pipe is contacted. To allow theblades to overlap, the tracks are separated and spaced apart vertically.Fluid power from an external source, usually rig power, is plumbed tothe cylinders, with associated valving accessible to rig personnel forcontrol or the wiper blade positions. The tethers are arranged to allowthe frame to move laterally, within limits, within the container.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings wherein like captions pertain to like features,

FIG. 1 is a plan view of the preferred embodiment of the system.

FIG. 2 is a side view, in cutaway, taken along line 2--2 of FIG. 1.

FIGS. 3 and 4 are plan views, from the perspective of FIG. 1 showingonly selected elements in first the closed position, then the openposition.

FIG. 5 is a section of one part of the assembly of FIG. 4 taken alongline 5--5.

FIG. 6 is an orthagonal view of the assembly of FIG. 5 with none cutaway.

FIG. 7 is a side elevation of part of the system of FIG. 1 taken alongline 7--7.

DETAILED DESCRIPTION OF DRAWINGS

In the drawings, some features commonly used for manufacturing andmaintenance utility, such as threaded fasteners and weld beads and thelike, but not bearing on points of novelty, are omitted in the interestof descriptive clarity.

In FIG. 1, the view is down the axis of a well bore. Container 1 iscommonly fastened to a well head and represents the configuration thatmay be seen through the central opening of a rig floor. The wiper blades6 and 7 are in the closed position, that position used to strip fluidfrom pipe, not shown, moving upward through the opening formed by arcs6a and 7a. Wiper blades 6 and 7 are quite resilient, usually rubber, andarcs 6a and 7a may be only narrow slits before being deformed into arcsas shown when forced against a pipe periphery.

The frame comprises opposed rail assemblies 2a and 2b, spaced apart byplates 2m and 2n. In channels, shown more clearly later, wiper carriers3 and 4 move outward from the position shown to the right and leftrespectively, urged by power cylinders 5 attached to the frame and thecarriers. Cylinders 5 actuate carrier 3 by way of rod and clevis 5a andcarrier lugs 3b. A similar set of cylinders 10 (not shown) is situatedbelow with rods extending to the left to actuate carrier 4. Thecylinders may have internal springs to urge the carriers open, and usefluid power only to close the wipers as shown.

Fluid power, usually rig air pressure, delivered by external plumbing toports 9a moves through hose 9 and inputs 5b, (and 10b not shown) toactuate the cylinders. The wiper lugs, 3b shown, extend through the railassemblies by way of notches 2d and 2j. The cylinders are bolted to theside of the frame.

In FIG. 2, some details are shown which can be more clearly seen in FIG.7. The inside of rail assembly 2a is shown. Wiper carrier 4 rests onwear rail 2f which is welded to the frame. Carrier 3 rests on top ofcarrier 4 when closed and is supported by confining rail 2g when movedto the open position. Rail 2g is welded to the rail assembly. Carrier 4is confined by confining rail 2h when it moves to the left to the openposition.

In some cases, rails 2g and 2h are replaced by a single rail extendingthe full length of the rail assembly, separating the carriers andproviding a supporting wear rail for carrier 3 and a confining rail forcarrier 4.

The carriers are structurally identical with lugs extending throughnotches 2d for carrier 3 and notches 2j for carrier 4. Rail assemblies2a and 2b are functionally identical configured for opposed location.

Container 1 has walls 1a to retrieve splash and dished basin 1b with atubular extension to well attachment flange 1d. Rails 1c are welded tothe basin to support the frame and are ported to allow fluid to pass tobore 1e. Bore 1e is the upper end of the well bore when in field use.

Two tethers 8 extend from container lugs 1f to frame lugs 2k to preventrotation of the frame relative to the container. The tethers may beflexible to allow the frame to move about laterally some amount in thecontainer. To prevent rotation in either direction, rigid tetherspivotably attached to the lugs may be used. Hose 9 is looped to allowlateral movement of the frame.

FIGS. 3 and 4 show the closed and the open relationships of the wipercarriers 3 and 4 and the attached wiper blades 6 and 7. No frame and noattachments are shown. Carrier 3 slides atop carrier 4. When closed,they have a stacked relationship. When open, only the inner ends of thecarriers overlap. Pins 3c and 4c secure the wiper blades within thesecuring grooves of the carriers.

FIG. 5 shows carrier 4, sectioned through the center along lines 5--5 ofFIG. 4. Dotted pin 4c is shown out of position but shows the locationrelative to the receiving groove 4a.

FIG. 6 is a view of the right end of the carrier and blade of FIG. 5,with the total width shown.

FIG. 7 shows the empty frame (view from the right end, FIG. 2), withcylinder sets 5 and 10 attached. Frame lugs 2k are shown. Cylinders 10are below cylinders 5 and have rods on the far end, out of view. Ports10b, like ports 5b, are for fluid pressure to operate the cylinders. Ifunbiased cylinders are used, each cylinder is provided with two suchports for fluid forced movement of the associated rods in both openingand closing actions. Such arrangements are well established in the artand are not shown. For such arrangements, two hoses such as 9 are neededand the external valving, also in the art, is used to select the actionneeded.

From the foregoing, it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the method and apparatus.

It will be understood that certain features and subcombinatIons are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the apparatus and method ofthis invention without departing from the scope thereof, it is to beunderstood that all matter herein set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limitingsense.

The invention having been described, I claim:
 1. In a pipe wiperassembly for stripping fluid from the outer surface of a well string,the assembly comprising a container having side walls, a pair of pipewiper blades situated within said container and movable between an openposition, wherein they are disassociated from the well string, and aclosed position, wherein they are pressed against the well string,theimprovement comprising: a frame situated within said container, forlimited horizontal movement therein, having a horizontal guideway toaccept said pipe wiper blades for movement from opposite sides of saidwell string between said open and said closed positions; a pair of fluidpower cylinder assemblies for each of said pipe wiper blades, mounted onsaid frame, arranged for linking said frame and said pipe wiper bladefor movement between said open and said closed positions; and flexiblemeans, connected to said fluid power cylinder assembly, for supplyingfluid power thereto.
 2. The pipe wiper assembly of claim 1 wherein saidpipe wiper blades are vertically separated and arranged to overlap whenin said closed position.
 3. The pipe wiper assembly of claim 2 whereinsaid guideway is divided into an upper portion for one said pipe wiperblade by a supporting wear plate attached to said frame and a lowerportion for the other of said pipe wiper blades.
 4. The pipe wiperassembly of claim 1 wherein said pipe wiper blades each comprise a rigidcarrier portion and a flexible wiper portion thereto attached andarranged to contact said well string and flex to conform to a portion ofthe circumference of said well string.
 5. The pipe wiper assembly ofclaim 1 wherein at least two flexible tethers extend from said frame tosaid container to limit rotation of said frame about said well string.6. An improved wiper assembly for stripping fluid from the outer surfaceof a well string, the assembly comprising, a container with side walls,a frame disposed for some horizontal movement therein, said frame havingat least one horizontal guideway therein, a pair of opposed wiper bladessituated in said guideway for horizontal movement therein between anopen position, wherein they are dissassociated from said well string,and a closed position, wherein they are pressed against said wellstring,the improvement comprising: a fluid powered cylinder, piston, androd assembly mounted on each of two sides of said frame for each of saidwiper blades and connected to said wiper blades for opening and closingthem, said rods attached to one of said wiper blades extending in anopposite horizontal direction relative to said rods for the other saidwiper blade, and flexible fluid power hoses for said fluid powercylinders arranged to provide fluid power to actuate said wiper bladesbetween said positions.
 7. The improved wiper assembly of claim 6wherein each of said wiper blades is provided with a lug on each of twosides extending through openings in said frame for attachment to saidrods.
 8. The improved wiper assembly of claim 6 wherein each of saidwiper blades comprises a flexible wiper element attached to a rigidcarrier.
 9. The improved wiper assembly of claim 6 wherein said wiperblades are positioned in a vertical stacked relationship with one wiperblade generally disposed above the other when in said closed position.10. The improved wiper assembly of claim 6 wherein said wiper bladesoverlap when in said closed position.
 11. The improved wiper assembly ofclaim 6 wherein at least two tethers are attached to, and extendbetween, said frame and said container and are arranged to accept somehorizontal movement, but limit rotation, of said frame relative to saidcontainer.
 12. The improved wiper assembly of claim 6 wherein saidflexible fluid power hoses comprise a single hose, divided to providefluid power simultaneously to all said fluid power cylinders to movethem collectively toward at least said closed position.
 13. The improvedwiper assembly of claim 6 wherein each of said fluid power cylinder,piston, and rod assemblies is spring biased to urge said wiper bladestoward said open position.
 14. The improved wiper assembly of claim 6wherein said fluid power cylinder, piston, and rod assemblies areprovided with fluid power hoses arranged provide fluid power to movesaid wiper blades, collectively, toward each of said positions.
 15. Theimproved wiper assembly of claim 6 wherein said guideway is divided intoan upper and a lower portion, said division defined by at least oneframe member providing support for one said wiper blade independently ofthe other of said wiper blades.